A Harvard physicist finds that the "Enchanted Islands" are not always pretty.

I traveled to the Galápagos Islands expecting to be amazed. After all, these dry volcanic islands are the well-known locus of Darwinian legends. Yet on my recent visit to this archipelago where sea lions rule the coast, marine iguanas and crabs congregate on shoreline rocks, birds display oddly colored feet and amusing faces, and the hotel rooms (where they exist) face away from the sea (if there are windows at all), I found that despite the many peculiarities, I initially couldn't pinpoint precisely what makes the Galápagos so special.

While in Australia last year, I was constantly struck by how different the vegetation was from any place I'd ever seen, how much brighter and more beautiful the birds were, and how all the mammals looked and acted differently—possessing pouches and moving via hops, among other peculiarities. I expected the Galápagos's fauna and flora to be even stranger, but that was not really the case. I began to understand why Darwin's book was entitled The Origin of Species and not, say, Entirely Out-of-the-Blue Creatures. Species differentiate among plants and animals, but not necessarily in a very striking way. Much of what I saw was peculiar, but not so different from what you might find on the South American continent or on other tropical islands. But, of course, that had been essential to Darwin's insightful observations.

That's not to say that the Galápagos are not unique and intriguing. The islands are notable for their distance from the Ecuadoran mainland and for their arid volcanic terrain, which produced the Galápagos's most striking and fortuitous distinction: the relative absence of people (and other predators). The Polynesians didn't settle there as they did on many Pacific islands, since there was nowhere to grow food or build the settlements they were accustomed to. The islands are occupied mainly by plants, reptiles, and birds, with only sea lions and a few thousand human residents—currently living in the 3 percent of the region that isn't protected national parkland—to represent the mammals. Given the long absence of predators, creatures here are totally unafraid. If anything, they're curious and approach closely to check you out. I had sharks swim up to my feet and a finch hop from one knee to the other, not to mention tons of sea lions who kept coming out to play when I was in the water. Even snorkeling, I had a whale shark come to swim right under me, and a white-tipped reef shark came so close I had a good look at its smile.

I was in the Galápagos to attend the World Summit on Physics, a four-day conference on theories that go beyond the "standard model" of particles and forces. International academic conferences are a new thing for the village of Puerto Baquerizo Moreno—capital of the Galápagos archipelago and its oldest settlement. We were the second major meeting. The first was on evolution, which certainly seems a more natural fit. Much of the evidence for Darwin's theory came from studying species on the Galápagos, though it's worth noting that Darwin didn't make his famous transition from creationist to evolutionist there, but only later, back in London, when studying his collections. And his published evidence was based on plants, not the famous Galápagos finches, since Darwin had neglected to record which island the different finch species he returned with came from.

The venue was less logical for us than it was for biologists, but we nonetheless had a fascinating and amusing adventure. The University of Ecuador recently realized it can lure distinguished academics to the islands since many people are eager to visit—in this case, 100 prominent theoretical and experimental particle physicists, including two Nobel Prize winners who were repeatedly and almost comically feted by the local politicians. The first evening we were treated to a reception and some speeches in which the local notables took us very seriously—much more seriously than we took ourselves (with perhaps a few exceptions).

Most of us flew into Quito and were shepherded onto an early morning chartered flight to San Cristóbal. This trip was my first visit to South America, so some of the odd cultural features that I encountered upon arrival were probably not specific to this region. There's a strange superposition of an exotic island paradise and a touristed town that is either falling apart or not quite built, not to mention the naval base that occupies a good part of the coast near the town and the posting advertising the local "armada." However, as I shifted my focus to nature and learned to ignore the ugly architecture, I realized I was, in fact, in a spectacular location.

After a few days, I began to see the charm of the town, its stores, and its friendly inhabitants. We arrived in the middle of the World Cup—an event impossible to forget in any inhabited region of South America. Walking around town was like wandering through a big house with the television on in every room, so dense were the shops and counters with TVs loudly sharing the game. My talk on a far more remote subject, "Gravitational Waves From Warped Extra-Dimensional Geometry," was almost delayed by a tied score until Beckham sent Ecuador out of the running.

A delay would have been a problem since the World Summit's schedule was very tightly packed. In fact, if you went to all the talks you would (a) cease to pay attention and (b) never have a chance to swim or snorkel, which would be a shame because you would miss out on the local black marine iguanas, the black fish, and black sea turtles in the water, as well as the black crabs near the shore. (The camouflage of these creatures on the black igneous rock was fascinating, but not very colorful.) But no matter what you did, you couldn't miss the sea lions. I used to think that sea lions were kind of fun (probably from going to SeaWorld), but these were fairly aggressive. You couldn't enter the water without a sea lion purposefully or playfully getting in your way at some point. One actually chased a couple of us when we tried to get a better look at an iguana. Have you ever seen a sea lion run? These cumbersome creatures can move rather efficiently on their superficially clumsy, small flippers.

Fortunately, the organizers relented and allowed us a full day for exploring. The highlight was definitely the aquatic excursion to Leon Dormido, also known as Kicker Rock (most places in the Galápagos have both a British and a Spanish name), a piece of a lava cone that juts out of the water a short boat ride away from San Cristóbal. Even before entering the water, we were treated to a view of the fabulous 500-foot-high rock formation, which looks sphinxlike from one perspective—hence the Spanish name Leon Dormido, or Sleeping Lion—but appears simply as a dramatically cleft vertical island when viewed up close. I was treated to my first sight of blue-footed and Nazca boobies. And en route we saw frigate birds with their red neck pouches blown up so large I momentarily thought they might be plastic balls, until I remembered that no one lives there.

I was lucky to join a scuba tour that one of the physicists had organized (though I did regret not knowing Spanish, as the route and much else had to be translated—a little disconcerting in what from my novice's perspective appeared to be a matter of life and death). During our dive, we saw a shark or two as well as some fish and the steep vertical face of the rock channel we were exploring. But the biggest treat arrived while I was snorkeling afterwards, when I was treated to a swim with a whale shark—a filter feeder, not a predator—so close that our local guide, Diego, could pet its dorsal fin (I have my limits). This was really lucky—Diego hadn't seen any of these sharks in five years of diving! It was relatively small, about four or five meters, and had fish attached to its tail and its characteristic white spots. It definitely made the day.

Before leaving the conference, I explored a hidden snorkeling site on San Cristóbal that was protected under rocky cliffs. The walk and swim were more fabulous than anything I'd yet seen on the island: The views were more dramatic, the vegetation more inviting, and the shoreline more pristine. There were schools of the usual black fish—but these had green tails—and there were also a few more colorful species. When I swam back, I realized it was getting late and I had lost track of my starting point. Suddenly the place with its rocky shoreline covered with black crabs and rising cliffs seemed foreign and a bit daunting. When a sea lion jumped in to play, I was in no mood to accommodate it.

But once safely on land, as the sun dropped low and only a few people sat nearby, I felt like I had discovered a different, more inviting place. The feeling returned that evening as some of us looked at the stars in the Southern Hemisphere sky, which is spectacular and different, with the Southern Cross riding high and the Big Dipper sinking below the horizon.

However, that feeling was soon lost when I took a boat tour after the conference. Although the source of the attraction of the Galápagos, both for Darwin and for tourists today, is the paucity of civilization that has allowed it to evade human influence, Ecuadoran law says that to visit the uninhabited islands you have to be on a tour in the company of a "naturalist." This means that in effect you are always stuck with large groups of people and a chatty guide when you visit land that has been declared a national park. The subtlety of Darwin's ideas and the isolation of the territory can be easily forgotten in such extensive company. When you're not marching in lockstep, you're confined to a boat with virtually no independence. What I usually love about traveling is the sense of discovery and autonomy, which is entirely lost when someone takes you to a set series of places and doesn't allow you out of his view. Having attended the physics conference, my time for touring was constrained, so I couldn't get on one of the smaller boats (which I would strongly recommend). Like all the rest of the conference participants who took a tour, I was on a boat with 100 other people.

Mind you, we did see stunning vistas and magnificently weird and exotic animals unfazed by the presence of humans. We saw not only the iguanas and frigate birds familiar from San Cristóbal but also blue-footed and red-footed boobies, white-tipped reef sharks, more turtles, land iguanas, and other creatures. Virtually none of these animals are classically cute—the reptiles are bizarre, the sea lions are smelly and slimy, and the birds often resemble vultures and seagulls, or else they appear slightly foolish or ungainly—but they were all fascinating to observe.

I hadn't really anticipated the type of landscape we encountered, as I had the images of pristine volcanic rock from the 2003 movie Master and Commander in mind. Yet only a few places in the Galápagos had this terrain in clear view. Instead, much of the islands' surface is covered by abundant but drab vegetation, including the dry gray "holy stick" tree. It was plants such as these that Captain Robert Fitzroy of the Beagle must have observed when he described "the dry and wretched looking thickets of the coast land." The islands are deserts, but deserts (like most) in which life frantically tries to establish itself. There are very few flowers, and even those Darwin called "insignificant, ugly little flowers"—after all, the insects that generally spread seeds or pester mammals are largely absent as well (a nice bonus if you hate bug bites as much as I do). But there are many cacti and other plants, some of which descend right down to the ocean in places. Of course, it's precisely this meager environment that stimulated the competition for resources that made evolution so rapid and visible here.

Toward the end of my boat trip, tired of my regimented tour, I resolved to go diving once again, off Santa Cruz Island, before returning home. We weren't in the best dive spot—the Galápagos has truly remarkable locations where you can swim through schools of hammerhead sharks, for example—but it wasn't bad. One of the nicest moments (aside from the shark in my face and the ray undulating below) was, oddly enough, a result of my getting seasick. So that I could rest on dry land for a bit, our boat pulled up to a dock away from the island's very touristed port. The dive master and I relaxed by the side of a road in a little idyllic spot: There was a pond, and even a few flowers and birds hopping around. It was here, as a finch hopped onto my knees, that my dive master, who lived nearby, observed, "This is the real Galápagos." And it was true. Here, once again, the Galápagos Islands became a magical place.

If you want to go to the Galápagos yourself, you might check out these tour companies: Enchanted Expeditions (Guide Juan Tapia can identify the different species of Darwin's finches by sight and by song) and Andando Tours (representative of Angermeyer Cruises).